What is a Botnet?
A botnet is a network of infected machines (zombies) that are under control of the attacker. The hacker, known as a bot herder, can use the many devices in the botnet to carry out large-scale attacks for their own personal gain or for a fee from other hackers who want to hire them.
Bots are generally spread by malware, and are designed to quietly infect machines without the user’s knowledge. Once an infected device becomes part of a botnet, the herder can remotely execute commands to the zombie computers. These commands can range from hijacking the computer’s resources to sending e-mail spam, or stealing financial information. The bots can also be used to distribute viruses, or mine Bitcoins.
Cybercriminals can rent out their botnets on the black market for large profits. This has become one of the most profitable business models for software developers and cybercriminals. A large botnet can be used for a variety of attacks, from massive Distributed Denial of Service (DDOS) attacks to stealing financial information.
Most commonly, the infected devices are personal computers and mobile phones that don’t have anti-malware running on them. However, even some IoT devices are being co-opted into botnets, and are a growing concern for cybersecurity teams. Educating users on the dangers of malware, and having robust antivirus software programs installed, can help reduce the risk of infection. A strong password and multi-factor authentication are also helpful, as is a good practice of disabling unnecessary services on computers and IoT devices.